Add support for Python3.12

[kunalsz]

In reference to the issue #1576

Changes made

• Python3.12 has been added to the Dockerfile,Makefile and CI Workflow

[Rishi-source]

Hi @kunalsz ,I think Directly adding support for python 3.12 would not do the job coz some libraries or their version are not compatible in python 3.12 as mentioned by @Dedsec0098 in one of his issue related to failing tests #1782 which means that some tests would be failing in 3.12. so you have to take a look on all of such issues which could come when workflow file runs on each pull request otherwise currently your code is cancelling the job as you can see in the image below.
jobs for python 3.9,3.10.3.11 are also giving error

Run make dev envfile
-> Bootstrap the virtualenv with PYTHON_EXE=python3.12
make: python3.12: Command not found
make: *** [Makefile:51: virtualenv] Error [12](https://github.com/kunalsz/vulnerablecode/actions/runs/13607460788/job/38041005157#step:5:13)7

PYTHON_EXE should not be changed imo as I am working on python 3.13 still I use python3 while running any python command on cli.